Biobased cellulose for future needs

Malin From is industrial PhD student in FORIC research school at FSCN research centre Mid Sweden University. She is working on regeneration of cellulose to create sustainable biobased cellulose films that can replace plastic. Malin holds a MSc in Chemical Engineering from Uppsala University and is currently employed as a PhD student at AkzoNobel in Sundsvall.

"We get cellulose from Domsjö Fabriker and work in the lab to study and develop different technologies for making cellulosic films," says Malin.

Wood fibre contains cellulose, a sugar polymer consisting of many glucose molecules that are assembled in a long line. If the cellulose molecules are dissolved and regenerated, the resulting film is quite similar to traditional plastic, but the raw material is biobased and renewable. The cellulose is first ground to a fine wadding batt which is mixed in water with various additives and mixed in -12 degrees C. The mixture is frozen and mixed several times to dissolve the cellulose into a translucent liquid form. The cellulose solution is then applied as a thin layer before it is regenerated in different types of regeneration bath to be precipitated into a film. The molecular chain can also be modified with different side groups, which will result in different properties of the regenerated film, for example, the material may range from crooked to elastic and from a material that acts as a gas membrane to one that can hold gas for an extended period of time. It is a complex process with many different stages, where much of the research is about understanding the underlying mechanisms through experiments and analysis to find the best combination in the different steps.

With proper modifications, cellulose could replace traditional plastic in multiple applications. The research is conducted in cooperation with the partner companies AkzoNobel, RISE Processum and Domsjö Fabriker.

"It is interesting to have research and development work with clear objectives where I can develop my knowledge with other researchers and build my network of contacts with business companies," says Malin.

The aim of the PhD project is to understand how cellulose is dissolved and regenerated in films and how it affects mechanical properties and barrier properties. The goal is also to gain knowledge about how to customize cellulose molecules with different side groups to obtain desired properties of the material.